The present invention is generally directed to a method and apparatus for processing a stream of suspended or dispersed particles. More specifically the present invention is directed to method and apparatus for fine particle filtration by way of deagglomeration of a liquid or gas stream of agglomerated particles and thereafter separating the deagglomerated particles from any residual agglomerated particles and other larger size particulate process stream contaminants. The present invention is also directed to method and apparatus for disrupting agglomerated primary particles with, for example, an ultrasonic agitator or disrupter system which enables efficient and controlled disruption of particulate agglomerates into primary particulates and permits efficient and controlled separation of the primary particles from the agglomerates. The present invention is also directed to method and apparatus with in-situ ultrasonic particulate cleaning capability and which capability permits convenient liberation of larger size particulate materials which particles may foul or interfere with the normal operating efficiency and efficacy of the particulate process stream, for example, blinding a filter member. The cleaning capability permits convenient cleaning of process stream componentry, for example, filter elements, plumbing conduits, valves, tanks, and the like components. The present invention provides a system, apparatus, and method for separating or removing larger size agglomerated particulates or contaminants from smaller primary particles, for example, agglomerated toner particles from primary toner particles, and for example, agglomerated photoreceptor charge generation pigments from the base or primary pigment particles. These and other embodiments of the present invention are disclosed herein.
In a typical electrostatographic printing system, a light image or digital image of an original to be reproduced is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles which are commonly referred to as toner. The visible toner image is then in a loose powdered form and can be easily disturbed or destroyed. The toner image is usually fixed or fused upon a support which may be the photosensitive member itself or another support sheet such as plain paper. Other related marking technologies are known, for example, liquid immersion development, and solid or liquid ink jet imaging technologies wherein a liquid, solid, molten, sublimed, and the like marking formulations are deposited onto an imaging member, imaging intermediate member, or image receiver and wherein the marking or imaging material is typically conveniently packaged for end-user or operator installation. Thus it is readily apparent to one of ordinary skill in the art that embodiments of the present invention are readily adaptable to formulation and manufacture of marking formulations and other marking materials, for example, related consumable materials, such as, replenishers, photoreceptors, fuser rolls, backer rolls, fuser oils, cleaning formulations, photographic coupler dispersions, pigmented inks for photographic realistic printing, papers or transparency stock, specialty coatings for papers or transparency stock, such as high quality or specialty receivers, xe2x80x9cTxe2x80x9d-shirt transfers, and the like materials.
In embodiments, the system and methods of present invention provide unexpected benefits and superior performance levels to material analysts or operators, for example, in facilitating process efficiency with minimized down time or uninterrupted continuous performance, avoiding materials waste or downtime, and avoiding productivity losses associated therewith that results from filter clogging or fouling. These and other advantages of the present invention are illustrated herein.
In the aforementioned commonly owned and assigned U.S. Pat. No. 4,707,112, issued Nov. 17, 1987, to Hartmann, which discloses an electrophotographic printing machine in which an electrostatic latent image recorded on a photoconductive surface is developed with a liquid developer material comprising at least a liquid carrier having marking particles therein. The liquid developer material is furnished to the electrostatic latent image recorded on the photoconductive surface in a development zone to develop the latent image. Marking particles are substantially uniformly dispersed, for example, with mechanical or acoustical devices, in the liquid carrier of the liquid developer material at the entrance to the development zone so as deflocculate the marking particles.
In the aforementioned commonly owned and assigned U.S. Pat. No. 4,692,188, issued Sep. 8, 1987, to Ober, discloses a process for the preparation of ink compositions useful for jet printing processes which comprises (1) dissolving in water immiscible organic solvent a polymer composition and an organic oil soluble dye; (2) adding an aqueous phase water surfactant mixture thereto; (3) affecting emulsification thereof, for example, with ultrasound; and (4) subsequently evaporating from the aforementioned mixture the solvent thereby resulting, in an ink with the dye trapped in the polymer particles suspended in the aqueous phase.
In U.S. Pat. Nos. 4,741,841, issued, May 3, 1988, to Borre et al., there is disclosed a method and apparatus for particle separation where particulates which are less than and greater than a predetermined size and are entrained in a fluid are separated according to their respective sizes by passing the fluid and entrained particulates through a porous, cross-flow separator element while continuously vibrating the separator element to prevent buildup of particulates on the upstream side of the separator element.
Other references of interest include U.S. Pat. Nos. 5,209,822; 4,594,152; 5,338,451; 5,466,384; 3,750,889; and 5,628,909, which patents generally relate to cross-flow filtration but without vibration. The aforementioned patent references are incorporated in their entirety by reference herein.
There remains a need for a system and method for deagglomerating agglomerated particles into primary particles and for accomplishing subsequent unit operations on the primary particles, such as, separation of the primary particles from any agglomerated particles or contaminant particles, or coating of the primary particle dispersions or suspensions.
The system and method of the present invention is useful, for example, in the preparation of materials for electrophotographic imaging and printing systems and especially color and digital applications, particle size analysis and diagnostics, particle size development and management, and the like applications. As a specific example, the present invention can be used in the design and manufacture of superior flow and charge performing particulate materials, such as toner materials, and including toner surface additive materials, such as silicas, surface treated silicas, polymeric surface additive particles, and the like additives. Another area of application of the system, apparatus, and method of the present invention, includes for example, as a useful tool in the design, manufacture, diagnosis, or trouble shooting performance, of particle materials or particulate containing formulations, such as found in the imaging materials technology area, for xerography, ionography, silver halide photography, and the like technology areas. Other areas of application of the system, apparatus, and method of the present invention, include for example, pharmaceutical dosage form preparation and processing, including for example, timed release, delayed release, or controlled release formulations of primary particle or agglomerated particle formulations. Still other areas of application of the system, apparatus, and method of the present invention, include for example, particulate emission analysis, that is measurement of aggregated or agglomerated materials comprised of aggregates or combinations of primary particles. Representative technology areas include for example: environmental testing and analysis; pesticide and crop chemical formulation development and analysis; foodstuff formulation development and analysis; biotechnology formulation development and assays, for example, bacterial and viral agglomerate particle analysis; wear analysis of moving parts, for example, fragmented or wear particulates and the analysis of the aggregates thereof, such as the extent of agglomeration and the strength of the agglomerates.
Embodiments of the present invention, include:
A method comprising:
sonicating a stream containing a dispersion comprised of agglomerated primary particles; and
filtering the resulting sonicated stream containing a dispersion comprised of deagglomerated primary particles;
An apparatus comprising:
an sonicator, such as an ultrasonicator, adapted to sonicate a stream of a liquid dispersion of agglomerated primary particles; and
a filter member adapted to filter the resulting sonicated stream containing a dispersion of de-agglomerated primary particles; and
An apparatus comprising:
a coater adapted to coat the above mentioned resulting filtered stream containing a dispersion of de-agglomerated primary particles onto a receiver.
These and other embodiments of the present invention are illustrated herein.